path: root/drivers/block/aoe/aoecmd.c

/* Copyright (c) 2006 Coraid, Inc.  See COPYING for GPL terms. */
/*
 * aoecmd.c
 * Filesystem request handling methods
 */

#include <linux/hdreg.h>
#include <linux/blkdev.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/genhd.h>
#include <asm/unaligned.h>
#include "aoe.h"

#define TIMERTICK (HZ / 10)
#define MINTIMER (2 * TIMERTICK)
#define MAXTIMER (HZ << 1)

static int aoe_deadsecs = 60 * 3;
module_param(aoe_deadsecs, int, 0644);
MODULE_PARM_DESC(aoe_deadsecs, "After aoe_deadsecs seconds, give up and fail dev.");

struct sk_buff *
new_skb(ulong len)
{
	struct sk_buff *skb;

	skb = alloc_skb(len, GFP_ATOMIC);
	if (skb) {
		skb->nh.raw = skb->mac.raw = skb->data;
		skb->protocol = __constant_htons(ETH_P_AOE);
		skb->priority = 0;
		skb->next = skb->prev = NULL;

		/* tell the network layer not to perform IP checksums
		 * or to get the NIC to do it
		 */
		skb->ip_summed = CHECKSUM_NONE;
	}
	return skb;
}

static struct frame *
getframe(struct aoedev *d, int tag)
{
	struct frame *f, *e;

	f = d->frames;
	e = f + d->nframes;
	for (; f<e; f++)
		if (f->tag == tag)
			return f;
	return NULL;
}

/*
 * Leave the top bit clear so we have tagspace for userland.
 * The bottom 16 bits are the xmit tick for rexmit/rttavg processing.
 * This driver reserves tag -1 to mean "unused frame."
 */
static int
newtag(struct aoedev *d)
{
	register ulong n;

	n = jiffies & 0xffff;
	return n |= (++d->lasttag & 0x7fff) << 16;
}

static int
aoehdr_atainit(struct aoedev *d, struct aoe_hdr *h)
{
	u32 host_tag = newtag(d);

	memcpy(h->src, d->ifp->dev_addr, sizeof h->src);
	memcpy(h->dst, d->addr, sizeof h->dst);
	h->type = __constant_cpu_to_be16(ETH_P_AOE);
	h->verfl = AOE_HVER;
	h->major = cpu_to_be16(d->aoemajor);
	h->minor = d->aoeminor;
	h->cmd = AOECMD_ATA;
	h->tag = cpu_to_be32(host_tag);

	return host_tag;
}

static inline void
put_lba(struct aoe_atahdr *ah, sector_t lba)
{
	ah->lba0 = lba;
	ah->lba1 = lba >>= 8;
	ah->lba2 = lba >>= 8;
	ah->lba3 = lba >>= 8;
	ah->lba4 = lba >>= 8;
	ah->lba5 = lba >>= 8;
}

static void
aoecmd_ata_rw(struct aoedev *d, struct frame *f)
{
	struct aoe_hdr *h;
	struct aoe_atahdr *ah;
	struct buf *buf;
	struct sk_buff *skb;
	ulong bcnt;
	register sector_t sector;
	char writebit, extbit;

	writebit = 0x10;
	extbit = 0x4;

	buf = d->inprocess;

	sector = buf->sector;
	bcnt = buf->bv_resid;
	if (bcnt > d->maxbcnt)
		bcnt = d->maxbcnt;

	/* initialize the headers & frame */
	skb = f->skb;
	h = aoe_hdr(skb);
	ah = (struct aoe_atahdr *) (h+1);
	skb_put(skb, sizeof *h + sizeof *ah);
	memset(h, 0, skb->len);
	f->tag = aoehdr_atainit(d, h);
	f->waited = 0;
	f->buf = buf;
	f->bufaddr = buf->bufaddr;
	f->bcnt = bcnt;
	f->lba = sector;

	/* set up ata header */
	ah->scnt = bcnt >> 9;
	put_lba(ah, sector);
	if (d->flags & DEVFL_EXT) {
		ah->aflags |= AOEAFL_EXT;
	} else {
		extbit = 0;
		ah->lba3 &= 0x0f;
		ah->lba3 |= 0xe0;	/* LBA bit + obsolete 0xa0 */
	}

	if (bio_data_dir(buf->bio) == WRITE) {
		skb_fill_page_desc(skb, 0, virt_to_page(f->bufaddr),
			offset_in_page(f->bufaddr), bcnt);
		ah->aflags |= AOEAFL_WRITE;
		skb->len += bcnt;
		skb->data_len = bcnt;
	} else {
		writebit = 0;
	}

	ah->cmdstat = WIN_READ | writebit | extbit;

	/* mark all tracking fields and load out */
	buf->nframesout += 1;
	buf->bufaddr += bcnt;
	buf->bv_resid -= bcnt;
/* printk(KERN_DEBUG "aoe: bv_resid=%ld\n", buf->bv_resid); */
	buf->resid -= bcnt;
	buf->sector += bcnt >> 9;
	if (buf->resid == 0) {
		d->inprocess = NULL;
	} else if (buf->bv_resid == 0) {
		buf->bv++;
		WARN_ON(buf->bv->bv_len == 0);
		buf->bv_resid <